Most, if not all, guitar players prefer that their instruments intonate correctly. That is to say, that their guitars play equally in tune at all points on the fingerboard. Correct intonation is achieved by the use of a bridge having means for the length adjustment of each string.
Virtually all acoustic guitars now in existence have no means for such adjustment. Their string lengths are determined by the location of one non-adjustable saddle installed on the instrument at the time of its manufacture.
Heretofore, a wide variety of bridges have been proposed and implemented for intonation adjustment.
One such bridge consisted of a slotted, wooden base whereby a saddle piece could be moved from one slot to the next to change the string length. This concept is illustrated in U.S. Pat. No. 934,678. This bridge had to be installed at the time of the instrument's manufacture or else undesirable modification and possible damage would have to be done to the guitar. Furthermore, it did not provide the continuous string length adjustment required for precise intonation. Users found this type of bridge unsatisfactory.
A variety of other adjustable bridge mechanisms are illustrated in the following U.S. Pat. Nos. 490,528; 688,272; 4,208,941; 4,464,970; and 4,768,414.
U.S. Pat. No. 4,768,414 shows small individual adjustable saddle units, one for each string and fitting in the anchor slot of the bridge. However, this structure has the disadvantage that when a string breaks, the adjustable saddle unit under the broken string can fall out and be lost.
U.S. Pat. No. 282,147 shows a bridge height adjustment.
Another bridge consisted of a metal chassis with six movable saddles for string length adjustment. While this bridge worked for solid body and archtop electric guitars, it was undesirable for acoustic guitars. Users found that the weight of the metal bridge subdued the vibration of the top of the instrument, diminishing the guitar's volume and tone. Furthermore, use of such bridge required extensive, irreversible modification to the acoustic guitar, greatly lowering the resale value of the instrument. In essence, guitarists found this type of bridge to be unusable on acoustic guitars. Examples of such adjustable bridges are found in U.S. Pat. Nos. 2,740,313 and 2,793,557.
Most guitarists, therefore, would find it desirable to have an intonation adjustable acoustic guitar bridge that is easy to install, yet does not detract from the instruments original utility. Desirably, it would not require any permanent modification of the guitar so it would allow the guitar to be changed back to its original condition.
Accordingly, the following are objects and advantages of the invention: to provide a bridge for individual string length adjustment for use on the acoustic guitar, to provide a bridge which anchors in the acoustic guitar's original saddle slot but can't fall out if one or several strings break, and which make any modification to the instrument unnecessary, and to provide a bridge with simultaneous string height and chassis tilt adjustment which allows the player to choose a comfortable playing feel and secures the bridge for improved note sustaining characteristics and prevents undesirable warpage and accompanying noise from the bridge.
In addition, there are the following additional objects and advantages: to provide an adjustable bridge for acoustic guitar that is inexpensive to manufacture, thus affordable to virtually every guitar owner, and to provide a bridge that allows for unobvious acoustic resonance and accompanying increase in sustaining characteristics of notes made possible by the precise harmonic tuning of string length.
Readers will find further objects and advantages of the invention from a consideration of the ensuing description and the accompanying drawings.